在 main.js 自定义 sticky 指令

Vue.directive('sticky', {
    
    
  // 当被绑定的元素插入到 DOM 中时……
  inserted(el,binding) {
    
    
    // 获取表格
    const thead = el.children[1]
    const tbody = el.children[2]
    // 获取滚动元素
    const scrollParent = document.querySelector(binding.value.parent)
    scrollParent.addEventListener('scroll', function(){
    
    
      // 获取thead距离顶部的距离
      let theadTop = thead.getBoundingClientRect().top
      if (theadTop <= binding.value.top) {
    
    
        thead.style.position = 'fixed'
        thead.style.zIndex = '2021'
        thead.style.top = binding.value.top + 'px'
        thead.style.width = tbody.offsetWidth + 'px'
      }
      // 判断是否需要回归原来位置
      let originally = tbody.getBoundingClientRect().top
      if (originally > binding.value.top) {
    
    
        thead.style.position = 'relative'
        thead.style.zIndex = '0'
        thead.style.top = 0 + 'px'
        thead.style.width = tbody.offsetWidth + 'px'
      }
      // 判断底部距离是否超过表头
      let goBeyond =tbody.getBoundingClientRect().bottom
      if (goBeyond <= thead.offsetHeight) {
    
    
        thead.style.position = 'relative'
        thead.style.zIndex = '0'
        thead.style.top = 0 + 'px'
        thead.style.width = tbody.offsetWidth + 'px'
      }
    })
  },
})

使用方法，top 为距离顶部位置，parent 滚动元素 ID

template>
    <el-table
    	v-sticky="{top: 150,parent:'#table_box'}"
      :data="tableData"
      style="width: 100%">
      <el-table-column
        prop="date"
        label="日期"
        width="180">
      </el-table-column>
      <el-table-column
        prop="name"
        label="姓名"
        width="180">
      </el-table-column>
      <el-table-column
        prop="address"
        label="地址">
      </el-table-column>
    </el-table>
  </template>